The present invention relates to a camera control device and, more particularly, to a camera control device for controlling the imaging (photographing) direction (panning and/or tilting) and the magnification (zooming).
Conventional means for remotely controlling the panning and/or tilting and zooming of a video camera include an operation lever, a joy stick, and a push button switch, each of which corresponds to rotations on two axes, and a button on a display which imitates any of these devices. When these devices are used, the rotational angle or the angular velocity is made correspond to the angle of the lever, or a rotation in a desired direction, such as a vertical or horizontal direction, is performed while the button is pushed. Analogously, zoom control is done by using a button or the like device which designates an operation to the wide-angle side or the telephoto side.
When, for example, panning or tilting is performed using the camera operating means or control device as described above, the camera pans or tilts in accordance with the operation, so the device is suitable for an operation which the user performs while monitoring the monitor screen. However, the device is inappropriate to operate or control a camera to a target position regardless of the current camera position.
Another method is possible in which the angles of a panning and tilting are directly input as numerical values and a camera is moved to the corresponding position under the control of a control device. In this case, however, an operator cannot sensibly recognize which region in the movable range of panning/tilting is within the field of view.
In remote diagnoses or television conference systems in which the circumstances of remote places need to be picked up by television cameras, an object to be picked up moves or objects are changed in many instances while a motion image is taken from a video camera and displayed on a display. In these cases, a user on the camera side need not always confirm the picking up range by directly monitoring the motion image on the display, since the user can identify the picked up object to some extent by checking the direction of the camera. However, if the camera is located in a remote place from both the display and the user, the user must change an object to be picked up by remotely changing the direction of the camera while monitoring the screen on which the motion image currently being picked up is displayed.
In these instances, the direction of the camera can be controlled more easily if the user can see not only a motion image within the limited range which can be picked up by the camera at once but also the circumstances over a wide area in the remote place capable of being picked up by the camera. Additionally, the presence is improved and the atmosphere is better understood when not only an object of interest but the scene in an entire remote place are displayed on the screen.
The circumstances over a broader range in a remote place cannot be communicated by motion images unless motion images taken by a wide-angle camera are displayed. Unfortunately, when the atmosphere is communicated by using wide-angle motion images, an object of interest also is displayed as a small image.
Methods by which this is prevented are to selectively display an image of an entire atmosphere (wide-angle) and an enlarged image (standard or telephoto) on a single display (or display window), and to simultaneously display two images taken by wide-angle and standard (or telephoto) cameras on two displays (or display windows). It is unfortunate that transmitting wide-angle and standard images using two cameras requires pairs of cameras, camera control devices, and image transmission lines.
To realize this with a single camera, the following methods are possible.
(1) Transmit a high-resolution motion image and display the image on a high-resolution, large screen.
(2) Transmit a high-resolution motion image and enlarge, where necessary, only an object of interest on the display side.
(3) Transmit a motion image with a normal pixel density and enlarge a portion of the image on the display side.
(4) Change the zoom ratio of a camera in a remote place.
In methods (1) and (2) described above, however, it is necessary to transmit motion images with a high definition (=large capacity). Consequently, in method (2) the image quality is degraded when an image is displayed in an enlarged scale. Also, in the methods other than method (1) it is not possible to simultaneously check the motion image over a wide area and the point of interest, i.e., two different images of wide-angle and standard ranges.